Fossilized Katydid Wings Sing Ancient Song

Below:

Next story in Science

A pair of fossilized insect wings is singing loud and clear,
thanks to the help of researchers. By analyzing a pair of
fossilized wings, researchers have recreated what a
165-million-year-old katydid would have sounded like.

"This is
a mating call basically, the male calls to the female and the
sound needs to be loud so it goes far, travels long distances and
the females listen to the sounds and decide whether or not to go
to the male," said study researcher Fernando Montealegre-Zapata,
of Bristol University in the United Kingdom.

Fossilized wings

The fossilized wings, discovered in China, are large, about 2.7
inches long (7 centimeters). This means the insect itself would
be about 4 inches (10 cm) long. The researchers compared the
insect's fossilized wings with those of 59 modern katydids to
figure out what sounds the ancient insect, named Archaboilus
musicus, made. [ See
images and hear the Ancient Katydid ]

" Males
have special sound generators in the wing. One wing is
modified with a file, a row of teeth, like a file, the other wing
has a scraper," Montealegre-Zapata said. "When they close the
wings, the teeth of the file produce vibrations that are
amplified as sound by the wing membranes."

Based on the researchers' calculations, the ancient katydids were
able to sing a pure tone using a single frequency of 6.4
kilohertz that lasted for 16 milliseconds. For comparison, the
ultrasonic ringtones kids' sometimes use on their phones (since
older people can no longer hear in that range) have frequencies
between 14 and 17 kHz.

This tone is fairly low in frequency, which means it can travel
farther than other, higher frequency tones. "That would suggest
that the animals are using it as a
private channel in the noisy forest with all the other
animals," Montealegre-Zapata said.

Forest song

To figure out how often the katydids would have made their calls,
the researchers looked to modern insects living in similar
environments. They found them in Malaysia, an island without
bats. Bats and other predators have pushed katydids to chirp at
higher frequencies and with fewer calls per second to avoid being
located, the researchers said.

"They have to reduce the rate of calling to avoid the bats
listening to them," Montealegre-Zapata said, adding that the
higher frequency means the calls won't travel as far so fewer
predators will likely hear them. "We used the calling rates of
these animals, which have the same body size as our fossil and no
bat predation and similar frequencies." The ancient katydid
probably sang out a few times every second.

Based on this new finding and other katydid fossils, the
high-frequency calls may go back 250 million to 200 million years
ago, according to Roy Plotnick, a researcher from the University
of Chicago who wasn't involved in the study. "We are pretty safe
saying this kind of communication could go all the way back to
the Triassic," Plotnick told LiveScience. "In 'Jurassic Park,'
they actually had
cricket sounds in the background, which is actually pretty
realistic."

The study was published today (Feb. 6) in the journal Proceedings
of the National Academies of Sciences.

You can follow LiveScience staff writer Jennifer Welsh on
Twitter @microbelover.
Follow LiveScience for the latest in science news and discoveries
on Twitter@livescienceand onFacebook.